Chapter 4 ______________________________________________________________ Maintenance
VAISALA____________________________________________________________________ 29
15.
The adjustment is done. Press
BACK
and
EXIT
to return to the
basic display.
16.
Turn off the MI70 and detach the connection cable.
Adjustment with HMI41
You can check and adjust the HMT100 relative humidity
measurement with the HMI41 indicator and HMP41/45/46 probes. A
HMI41-connection cable is needed, Vaisala order code: 25917ZZ.
There are three adjustment modes available: offset (dry point), gain
(wet point), and two-point adjustment. All of these can be performed
using the HMI41 either as a reference meter (for example when the
transmitter is mounted in an air-conditioning channel) or only as a
terminal for visualizing and setting the transmitter's RH reading.
Offset and gain adjustments are performed the same way and differ
only in internal calculations. Select offset adjustment when the
reference humidity is < 65 %RH and gain adjustment when the
reference humidity is
≥
65 %RH. Two-point adjustment is more
accurate, and includes both offset and gain corrections. For
performing two-point adjustment, you need two separate measurement
points with a difference of at least 50 %RH between them.
Follow the general directions of connecting the HMI41 to the
HMT100 and selecting the HMI41 calibrator function and then
continue according to the chosen adjustment method.
1
2
3
0505-187
Figure 18
Location of the HMI41 Calibration Connector
The following numbers refer to Figure 18 above:
1
=
HMI41 indicator
2
=
EXT connector
3
=
25917ZZ connection cable
